# Thread: integration problem

1. ## integration problem

Find the value of c for which

$\int^1_0 x^3sinh(cx) dx = 1$

I have no idead on how to work this out

2. ## Re: integration problem

You have a product of two functions so the first thing I would think of is "itegration by parts" which is the reverse of the "product rule" for derivatives.

Let $u= x^3$ and $dv= sinh(cx)dx$ so that $du= 3x^2dx$ and $v= \frac{1}{c}cosh(cx)$.

Do you see how the degree of x has been reduced? Now do that two more times.